Multi-biometric finger sensor including electric field sensing pixels and associated methods

ABSTRACT

A multi-biometric finger sensor includes a plurality of electric field fingerprint sensing pixels on an integrated circuit substrate for sensing an image of the user&#39;s finger, and at least one other finger biometric characteristic sensor on the integrated circuit substrate for sensing a finger biometric characteristic different than the image of the user&#39;s finger. Each of the electric field fingerprint sensing pixels may include an electric field sensing electrode, a guard shield surrounding the electric field sensing electrode, and an amplifier connected between the electric field sensing electrode and the guard shield. The sensor may also include a finger drive electrode adjacent the plurality of electric field sensing pixels, and a processor connected to the electric field fingerprint sensing pixels and the at least one other finger biometric characteristic sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit, under 35 U.S.C. 119(e), from U.S.Provisional Application Ser. No. 60/500,475, filed Sep. 5, 2003 and U.S.Provisional Application Ser. No. 60/536,305 filed Jan. 14, 2004, theentire disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to biometric sensing, and, moreparticularly to biometric sensing using integrated circuit biometricsensors and associated methods.

BACKGROUND OF THE INVENTION

Fingerprint sensing and matching is a reliable and widely used techniquefor personal identification or verification. In particular, a commonapproach to fingerprint identification involves scanning a samplefingerprint or an image thereof and storing the image and/or uniquecharacteristics of the fingerprint image. The characteristics of asample fingerprint may be compared to information for referencefingerprints already in a database to determine proper identification ofa person, such as for verification purposes.

A particularly advantageous approach to fingerprint sensing is disclosedin U.S. Pat. No. 5,953,441 to Setlak and assigned to the assignee of thepresent invention. The fingerprint sensor is an integrated circuitsensor that drives the user's finger with an electric field signal andsenses the electric field with an array of electric field sensing pixelson the integrated circuit substrate. The patent to Setlak also disclosesan approach to reduce spoofing by sensing another biometriccharacteristic of the user's finger, in particular, the same electricfield sensing pixels are used to determine a complex impedance of theobject presented to the sensor. Spoof reduction circuitry determines ifthe complex impedance of the presented object is indicative of a livefinger. In other words, the Setlak patent discloses a biometricauthentication approach that relies on multiple biometrics of the user'sfinger.

Other multi-biometric approaches may use various combinations of voicerecognition, facial recognition, fingerprint recognition, and signaturedynamics, for example. To satisfy the system, a user must satisfyseveral of the selected biometrics independently. Such systems may showenhanced selectivity over single biometric systems because false matchesin one biometric characteristic are uncorrelated to false matches to asecond biometric characteristic. Such a multi-biometric system may bemore difficult to spoof, because each of the biometrics needs to bespoofed to compromise the system as a whole.

Representative of multi-biometric systems is, for example, U.S. PatentApplication Publication No. 2002/0138768 to Murakami et al. Thisreference discloses sensing a heartbeat waveform that is substantially,but not necessarily completely unique, as a first biometric trait orcharacteristic. A second biological trait is used in conjunction withthe first biological trait that is preferably also a live physiologicaltrait. Examples of live, potentially substantially unique biologicaltraits include the depth of the various layers of epithelial tissue froma given point on an individual's skin surface. The density of aparticular kind of connective tissue, such as bone density, may beanother substantially unique histological trait. Likewise, the lightabsorption characteristics of skin tissue or the visual retinal patternsof an iris could be substantially unique traits. Along these lines, U.S.Patent Application Publication No. 2003/0128867 to Bennett and U.S. Pat.No. 6,483,929 to Murakami et al. both disclose a biometric system thatinjects infrared energy into the user's finger and senses resultinginfrared energy from the user's finger, such as to obtain the user'sheartbeat as a biometric.

U.S. Pat. No. 6,327,376 to Harkin discloses a multi-biometric sensorincluding capacitive sensing pixels below a glass transparent sensingsurface for sensing the ridge pattern of the user's finger. The sensormay also include an additional sensor of the contactless kind whichrelies for its sensing on the use of light, such as visible or infraredlight, that can be positioned behind the capacitive fingerprint sensingarray.

U.S. Pat. No. 6,560,352 to Rowe et al. discloses a biometric analysisbased on using near-ultraviolet, visible, very near-infrared, ornear-infrared energy and combinations thereof. U.S. Pat. No. 5,351,303to Willmore discloses a biometric system that senses and compares theinfrared image pattern from an individual's finger to another infraredimage pattern of the same finger stored within system memory. Otherbiometric sensing approaches are also disclosed using ultrasonicimaging, such as U.S. Pat. No. 5,689,576 to Schneider et al. and U.S.Pat. No. 5,737,439 to Lapsley et al., for example.

Unfortunately, the prior art multi-biometric systems may havesignificant drawbacks. Those having two different sensors are relativelycomplicated, and expensive to install and operate. Those that requiremultiple presentations of a user's body part, for example, areinconvenient. The requirement for multiple steps also slows the process.Independent sensors may also be spoofed independently. Of course, thereis a continuing need to also further develop even single biometricsensors and systems.

SUMMARY OF THE INVENTION

In view of the foregoing background, it is therefore an object of thepresent invention to provide an accurate, compact, and reliablemulti-biometric finger sensor and associated methods.

These and other objects, features and advantages in accordance with thepresent invention are provided by a multi-biometric finger sensorincluding a plurality of electric field fingerprint sensing pixels on anintegrated circuit substrate for sensing an image of the user's finger,and at least one other finger biometric characteristic sensor on theintegrated circuit substrate for sensing a finger biometriccharacteristic different than the image of the user's finger. Each ofthe electric field fingerprint sensing pixels may comprise an electricfield sensing electrode, a guard shield surrounding the electric fieldsensing electrode, and an amplifier connected between the electric fieldsensing electrode and the guard shield. The sensor may also include afinger drive electrode adjacent the plurality of electric field sensingpixels, and a processor connected to the electric field fingerprintsensing pixels and the at least one other finger biometriccharacteristic sensor. Accordingly, the electric field sensing pixelscan be combined with another biometric sensor to provide more accurateresults, for example, in a compact sensor package based on integratedcircuit technology.

For example, the at least one other finger biometric characteristicsensor may comprise a plurality of infrared sensing pixels. Each of theinfrared sensing pixels may be for sensing naturally emitted infraredradiation from the user's finger, for example.

Alternately or additionally, the at least one other finger biometriccharacteristic sensor may comprise at least one optical dispersionsensing pixel for sensing dispersed light from the user's finger. Inthese embodiments, an optical source may be provided for directing lightinto a user's finger when positioned adjacent the integrated circuitsubstrate. The light may propagate into and be dispersed by the user'sfinger so that at least a portion of the dispersed light exits theuser's finger in a direction toward the integrated circuit substrate.

The multi-biometric finger sensor apparatus may also include a matcherconnected to the electric field finger sensing pixels and the at leastone other biometric sensor. In some embodiments, the electric fieldfinger sensing pixels and the at least one other finger biometric sensormay operate based upon static placement of the user's finger adjacentthe integrated circuit substrate. In other embodiments, the electricfield finger sensing pixels and the at least one other finger biometricsensor may operate based upon sliding placement of the user's fingeradjacent the integrated circuit substrate.

The multi-biometric finger sensor apparatus may further comprise anuppermost dielectric passivation layer over the plurality of electricfield sensing pixels and the at least one other biometric sensor andupon which the user's finger is positioned. In addition, the integratedcircuit substrate may comprise silicon, or thin film substrate material,for example.

A method aspect of the invention is directed to multi-biometric fingersensing. The method may include receiving a user's finger adjacent anintegrated circuit substrate, and sensing an image of the user's fingerby using a plurality of electric field fingerprint sensing pixels on theintegrated circuit substrate. Each electric field fingerprint sensingpixel may comprise an electric field sensing electrode, a guard shieldsurrounding the electric field sensing electrode, and an amplifierconnected between the electric field sensing electrode and the guardshield. The method may also include sensing a finger biometriccharacteristic different than the image of the user's finger by using atleast one other finger biometric characteristic sensor on the integratedcircuit substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a first embodiment of an electronicdevice including an optical dispersion finger sensor in accordance withthe present invention.

FIG. 2 is a schematic diagram of a second embodiment of an electronicdevice including an optical dispersion finger sensor in accordance withthe present invention.

FIG. 3 is a more detailed schematic diagram, partially in section, of aportion of the electronic device as shown in FIG. 1.

FIG. 4 is a more detailed schematic diagram, partially in section, of aportion of the electronic device as shown in FIG. 2.

FIG. 5 is a greatly enlarged, schematic cross-sectional view of avariation of a portion of the infrared sensor as shown in FIG. 2.

FIG. 6 is a schematic top plan view of the optical dispersion sensor asshown in FIG. 2.

FIG. 7 is a schematic diagram of a first embodiment of an electronicdevice including an infrared finger sensor in accordance with thepresent invention.

FIG. 8 is a schematic diagram of a second embodiment of an electronicdevice including an infrared finger sensor in accordance with thepresent invention.

FIG. 9 is a more detailed schematic diagram, partially in section, of aportion of the electronic device as shown in FIG. 7.

FIG. 10 is a more detailed schematic diagram, partially in section, of aportion of the electronic device as shown in FIG. 8.

FIG. 11 is a schematic plan view of an infrared sensing pixel for theinfrared sensor as shown in FIG. 7.

FIG. 12 is a schematic cross-sectional view of an individual infraredantenna and thermocouple temperature sensor for the infrared sensingpixel as shown in FIG. 11.

FIG. 13 is a top plan view of the infrared antenna element andthermocouple sensor as shown in FIG. 12.

FIG. 14 is a schematic cross-sectional view of an alternate embodimentof an individual infrared antenna and thermocouple temperature sensorfor the infrared sensing pixel as shown in FIG. 11.

FIG. 15 is an enlarged schematic cross-sectional view through the middleof an individual infrared antenna and temperature sensor as shown inFIG. 12.

FIG. 16 is a top plan view of an individual infrared sensing pixel asmay be used in the infrared sensor as shown in FIG. 7.

FIG. 17 is an enlarged top plan view from the center portion of FIG. 16.

FIG. 18 is a schematic diagram of a first embodiment of an electronicdevice including a multi-biometric finger sensor in accordance with thepresent invention.

FIG. 19 is a schematic diagram of a second embodiment of an electronicdevice including a multi-biometric finger sensor in accordance with thepresent invention.

FIG. 20 is a more detailed schematic diagram, partially in section, of aportion of the electronic device as shown in FIG. 18.

FIG. 21 is a more detailed schematic diagram, partially in section, of aportion of the electronic device as shown in FIG. 19.

FIG. 22 is a schematic perspective view, partially in section, of anelectric field finger sensing pixel as may be used in themulti-biometric finger sensor as shown in FIG. 18.

FIG. 23 is a schematic top plan view of a portion of a multi-biometricsensor embodiment including electric field sensing pixels and opticaldispersion sensing pixels in accordance with the invention.

FIG. 24 is a schematic top plan view of a portion of another embodimentof a multi-biometric sensor including electric field sensing pixels andoptical dispersion sensing pixels in accordance with the invention.

FIG. 25 is a schematic diagram of a multi-biometric sensor as may beused in the device of FIG. 19 illustrating processing of biometric datatherefrom.

FIGS. 26-28 are graphs of collected and processed optical dispersiondata from three different users as may be obtained using the biometricsensor of FIG. 19.

FIG. 29 is a top plan view of a portion of yet another embodiment of amulti-biometric sensor including electric field sensing pixels andinfrared sensing pixels in accordance with the invention.

FIG. 30 is a schematic block diagram of another embodiment of amulti-biometric sensor in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout, and prime notation is used toindicate similar elements in alternate embodiments.

Referring initially to FIGS. 1-6, optical dispersion finger sensing as abiometric characteristic is first described. With particular referenceto FIGS. 1 and 3, the electronic device is in the exemplary form of acellular telephone 50 that includes a portable housing 51. The portablehousing 51 carries an optical dispersion finger sensor 55, and a lightedkeypad 52 that, in turn, includes a plurality of user operable inputkeys 53. The portable housing 51 also carries a processor 54 that isconnected to the optical dispersion sensor 55 and the optical source 57.A display 58 is illustratively carried by the upper portion of theportable housing 51 and is also connected to the processor 54.

The cellular phone 50 may also include a power source, such as arechargeable battery 62, carried by the portable housing 51 andconnected to the processor 54 and other electronic components within thehousing as will be appreciated by those skilled in the art. A memory 64is also connected to the processor 54. The optical source 57 is coupledto the keys 53 of the lighted keypad 52 by an optical guide 61 that maybe a plastic body for conducting light therethrough. The optical source57 may be an LED or electroluminescent source, for example.

Considered in other terms, the optical guide 61 may have an input 61 acoupled to the optical source 57 and a first output 61 b exposed throughan opening in the housing 51. A second output 61 c is illustrativelycoupled to the keys 53 as will be appreciated by those skilled in theart. The use of the onboard optical source 57 and the minor modificationto the optical guide 61 provides a relatively inexpensive approach tocouple light into the user's finger 70 for optical dispersion sensing.

Of course, in other embodiments a dedicated optical source may becarried by the portable housing 51. Such a dedicated optical sourcewould permit independent control from the lighted keypad 52, forexample.

The optical dispersion sensor 55 includes an integrated circuitsubstrate 72 and a plurality of optical dispersion sensing pixels 73 onthe integrated circuit substrate for sensing dispersed light from theuser's finger 70. In other embodiments, as few as one optical dispersionsensing pixel 73 may be used. More particularly, the optical sourceprovided by the exposed optical guide output 61 b directs light into auser's finger 70 when positioned adjacent the integrated circuitsubstrate 72. The light propagates into and is dispersed by the internaltissue of the user's finger 70 so that at least a portion of thedispersed light exits the user's finger in a direction toward integratedcircuit substrate 72. This dispersed light is captured by the opticalsensing pixels 73.

The processor 54 is connected to the optical dispersion sensing pixels73 for generating optical dispersion biometric data based upon dispersedlight from the user's finger 70. As will be discussed in greater detailbelow, the optical dispersion biometric data may comprise lightintensity data along at least one dimension of the user's finger 70, forexample. The optical dispersion biometric data may additionally oralternately comprise subdermal structure data for the user's finger.

In addition, the processor 54 further illustratively includes a matcher74 for determining a match between the optical dispersion biometric dataof the user's finger and stored optical dispersion biometric data for anenrolled user. This match determination, in turn, may be used by afunction enabler 75 of the processor to enable at least one devicefunction, such as permitting operation of the transmit and receivefunctions of the cellular telephone 50, for example. The matcher 74 andenabler 75 may be implemented on a CPU of the processor 54 operatingunder stored program control, as will be appreciated by those skilled inthe art without requiring further discussion herein.

Those of skill in the art will appreciate other device functions thatmay be controlled, such as access to data if the electronic device werea Personal Digital Assistant (PDA), for example. Of course, many otherelectronic devices may benefit from the optical dispersion fingersensing, and these devices may include other access limited functions.The optical dispersion biometric data may be accurately and efficientlyobtained using the compact integrated circuit-based sensor 55.

Another aspect of the optical dispersion sensor 55 is that itsprocessing may be self-contained on the integrated circuit 72 itself,or, as shown in the illustrated embodiment, the integrated circuit maycontain some of the processing circuitry 77. For example, pixel readingamplifiers and/or other image processing active devices may be providedon the substrate 72 using conventional CMOS technology. In yet otherembodiments, all or a majority of the signal processing circuitry may belocated off-chip. The integrated circuit substrate 72 may comprise asingle crystal silicon substrate in some embodiments, or a thin filmtechnology, such as a glass substrate, for example, in other embodimentsas will be appreciated by those skilled in the art.

The illustrated embodiment of the optical dispersion sensor 55 is astatic placement sensor. In other words, the size of the array of pixels73 is relatively large compared to a sliding placement sensor asdiscussed below. Also, for the static placement sensor 55, the processor54 generates the optical dispersion biometric data based upon staticplacement of the user's finger adjacent the integrated circuit substrate72.

Referring now more particularly to FIGS. 2, and 4-6 another class ofembodiments of optical dispersion finger sensor 55′ is now described. Inthese embodiments, the optical source is in the form of one or more LEDoptical sources 80 on the integrated circuit substrate 72′ itself. Theillustrated optical sensor 55, is also in the form of a slidingplacement sensor that has a smaller sensing area over which the userslides his finger 70′ as will be appreciated by those skilled in theart. In these embodiments, the processor 54′ may collect frames ofoptical dispersion data from the optical dispersion sensing pixels 73′.In other embodiments, the LED optical sources 80 could also be used onthe static placement sensor 55 described above.

Referring more specifically to FIG. 5, the plurality of opticaldispersion sensing pixels may comprise optical dispersion sensing pixels73 a′, 73 b′ having different frequency sensitivities f1, f2 within abroadband frequency range of the light from the LED 80 or optical source57 (FIG. 3). For example, as shown in the illustrated embodiment, theoptical dispersion sensing pixels may comprise buried optical detectorsin the form of P/N junction detectors 73 a′, 73 b′ being buried atdifferent depths to provide different frequency sensitivities. In otherwords, the height of the semiconductive material above a buried P/Nsensing junction 73 a′, 73 b′ can act as a filter for differentfrequencies. Other filtering or frequency selection techniques are alsocontemplated including filter coatings, for example. More than twofrequencies can also be selected by extension of these disclosedtechniques as will be appreciated by those skilled in the art.

Those other elements of the second embodiment of the cellular telephone50′ are similar to those of the first embodiment of the cellulartelephone 50 described above, and are indicated with prime notation.Accordingly, these elements require no further discussion herein.

Referring again to FIGS. 1-6, a method aspect is directed to opticaldispersion finger sensing. The method may comprise receiving a user'sfinger 70, 70′ adjacent an integrated circuit substrate 72, 72′, anddirecting light from an optical source 57, 80 into a user's finger whenpositioned adjacent the integrated circuit substrate. The light maypropagate into and be dispersed by the user's finger 70, 70′ so that atleast a portion of the dispersed light exits the user's finger in adirection toward the integrated circuit substrate 72, 72′. The methodmay also include sensing dispersed light from the user's finger using aplurality of optical dispersion sensing pixels 73, 73′ on the integratedcircuit substrate 72, 72′, and generating optical dispersion biometricdata based upon dispersed light from the user's finger 70, 70′. Themethod may also include enabling at least one device function based uponthe optical dispersion biometric data from the user's finger 70, 70′.

As will be appreciated by those skilled in the art, the same set ofoptical dispersion sensing pixels 73, 73′ may also be used forpulse/oximetry measurements. This may be done by extracting the cardiacpulse waveform and detecting minute changes in the red to infraredintensity ratio caused by the periodic arrival of freshly oxygenatedblood.

Referring now to FIGS. 7-10, various embodiments of infrared sensingpixel finger sensors 85, 85′ are first described. With particularreference to FIGS. 7 and 9, the electronic device is in the exemplaryform of a cellular telephone 80 that includes a portable housing 81. Theportable housing 81 carries an infrared finger sensor 85, and a lightedkeypad 82 that, in turn, includes a plurality of user operable inputkeys 83. The portable housing 81 also carries a processor 84 that isconnected to the infrared sensor 85 and the optical source 87 forlighting the keypad 82 via the optical guide 91. A display 88 isillustratively carried by the upper portion of the portable housing 81and is also connected to the processor 84.

The cellular phone 80 may also include a power source, such as arechargeable battery 92, carried by the portable housing 81 andconnected to the processor 84 and other electronic components within thehousing as will be appreciated by those skilled in the art. A memory 94is also connected to the processor 84.

The infrared sensor 85 includes an integrated circuit substrate 102 anda plurality of infrared sensing pixels 103 on the integrated circuitsubstrate for sensing infrared radiation naturally emitted fromsubdermal features of the user's finger 100. The processor 84 isconnected to the infrared sensing pixels 83 for generating the infraredbiometric data based upon naturally emitted radiation from subdermalfeatures of the user's finger 100.

The processor 84 further illustratively includes a matcher 104 fordetermining a match between the infrared biometric data of the user'sfinger and stored infrared biometric data for an enrolled user. Thismatch determination, in turn, may be used by a function enabler 105 ofthe processor 84 to enable at least one device function, such aspermitting operation of the transmit and receive functions of thecellular telephone 80, for example. The matcher 104 and enabler 105 maybe implemented on a CPU of the processor 84 operating under storedprogram control, as will be appreciated by those skilled in the artwithout requiring further discussion herein.

Those of skill in the art will appreciate other device functions thatmay be controlled, such as access to data if the electronic device werea PDA, for example. Of course, many other electronic devices may benefitfrom the infrared finger sensing, and these devices may include otheraccess limited functions. The infrared biometric data may be accuratelyand efficiently obtained using the compact integrated circuit-basedsensor 85.

Another aspect of the infrared sensor 85 is that its processing may beself-contained on the integrated circuit substrate 102 itself, or, asshown in the illustrated embodiment, the integrated circuit may containsome of the processing circuitry 107. For example, pixel readingamplifiers and/or other image processing active devices may be providedon the substrate 102 using conventional CMOS technology, for example. Inyet other embodiments, all or a majority of the signal processingcircuitry may be located off-chip. The integrated circuit substrate 102may preferably a silicon substrate as will be appreciated by thoseskilled in the art.

The illustrated embodiment of the infrared sensor 85 is a staticplacement sensor. In other words, the size of the array of pixels 103 isrelatively large compared to a sliding placement sensor as discussedbelow. Also, for the static placement sensor 105, the processor 104generates the infrared biometric data based upon static placement of theuser's finger adjacent the integrated circuit substrate 102.

Referring now more particularly to FIGS. 8 and 10, another class ofembodiments of infrared finger sensor 85′ is now described. In theseembodiments, the illustrated infrared sensor 85′ is in the form of asliding placement sensor that has a smaller sensing area over which theuser slides his finger 100′ as will be appreciated by those skilled inthe art. In these embodiments, the processor 104′ may collect frames ofinfrared image data from the infrared sensing pixels 103′.

Those other elements of the embodiment of the cellular telephone 80′shown in FIGS. 8 and 10 are similar to those of the embodiment of thecellular telephone 80 described above with respect to FIGS. 7 and 9, andare indicated with prime notation. Accordingly, these elements requireno further discussion herein.

Turning now additionally to FIGS. 11 through 17, other detailed aspectsof exemplary infrared sensing pixels 103 are now described. As shown inFIG. 11, for example, the infrared sensing pixel 103 includes an arrayof infrared sensing units 105 connected in series and whose output isfed to an infrared sensing amplifier (not shown). Each sensing unit 105includes an infrared antenna in the form of a bowtie dipole antenna 106having a relative small dimension to efficiently collect infrared energyas will be appreciated by those skilled in the art. For example, forinfrared radiation at a wavelength of about 7 microns, the length L ofthe dipole antenna 106 may be about 3.5 microns. The overall size of theinfrared sensing pixel 103 may be about 50 microns on each side as isconsistent with the dimensions of a typical electric field sensing pixelas will be described in greater detail below. The infrared sensingpixels 103 may be at a density of 125 pixels per inch to capturesubdermal patterns, and about 250 for ridge/valley imaging. Of course,other dimensions and types of infrared antennas may also be used as willbe appreciated by those skilled in the art.

As shown in FIGS. 12, 13 and 15, the infrared sensing unit 109 may beadvantageously formed using the various metal and polycrystallinelayers, separated by interlevel dielectric layers, as are commonly usedin semiconductor device processing. In the illustrated embodiment, theupper metal layer is patterned to form the two dipole antenna elements106 a, 106 b of the bowtie dipole antenna 106. An interlevel dielectriclayer 107 separates the dipole elements 106 a, 106 b from the underlyingantenna ground plane 108 provided by patterning the second metal layeras will be appreciated by those skilled in the art. Another interleveldielectric layer 111 separates the conductive antenna ground plane 108from the circuitry patterned using the first metal layer.

Two conductive vias 112 a, 112 b carry the signal from the dipoleantenna elements 106 a, 106 b to a temperature sensor in the form athermocouple having a measuring junction 114 and a reference junction115. Polysilicon dissipative regions 117 a, 117 b are used to match theimpedance of about 300 ohms. Tungsten via portions 120, 121illustratively connect to aluminum signal lines 122, 123, respectively,patterned on the first metal layer. The thermocouple junctions aredefined between the polysilicon of the first poly layer and the aluminumof the first metal layer as will be appreciated by those skilled in theart. The reference junction 115 is also shown relatively close to themeasuring junction 114 for clarity of explanation; however, in otheradvantageous embodiments, the reference junction may be spacedconsiderably further away from the measuring junction. As will also beunderstood by those of skill in the art, an upper passivation layer 125(FIG. 17) is also provided over the dipole antenna 106.

The infrared unit 105 uses a thermocouple rather than a resistor, forexample, to reduce power dissipation during imaging. Of course, in otherembodiments, a resistor or bolometer may be used as the temperaturesensor. Each infrared unit 105 may generate an output voltage of about0.2 to 20 microvolts, for example.

Another embodiment of an infrared sensing unit 105′ is explained withreference to FIG. 14. In this embodiment, the dropping resistor isprovided by a portion of the substrate 117′. The ohmic region could alsobe the channel of an FET allowing modulation of the power dissipated bychanging the gate voltage. The conductive vias 112 a′, 112 b′ allowconduction of the current wave from the dipole antenna 106′ through tothe lower layers of the integrated circuit device. In addition, adielectric layer 124 is provided that may provide additional ESDprotection as will be understood by those of skill in the art. Thoseother elements of the embodiment of FIG. 14, not specifically mentioned,are indicated by prime notation and are similar to elements describedabove with reference to FIGS. 12 and 13.

As shown in top plan views of FIGS. 16 and 17, radial strings ofinfrared antennas are positioned within a circular aperture 125 throughthe ground plane of an infrared sensing pixel 103. The measuringjunctions are positioned beneath the infrared antennas, while signallines connect to the reference junctions that are positioned on theperiphery of the overall pixel. The reference junctions are thereforeobscured from the infrared radiation by the ground plane as will beappreciated by those skilled in the art. Of course, other layouts forthe infrared pixels 103, 103′ are also contemplated.

Referring again to FIGS. 7-17, another method aspect of the inventiondirected to infrared finger sensing is now described. The method mayinclude receiving a user's finger 100, 100′ adjacent an integratedcircuit substrate 102, 102′, and sensing infrared radiation emitted fromsubdermal features of the user's finger 100, 100′ positioned adjacentthe integrated circuit substrate by using a plurality of infraredsensing pixels 103, 103′ on the integrated circuit substrate. Eachinfrared sensing pixel 103, 103′ may comprise at least one temperaturesensor, such as the thermocouple junctions 114, 115 and 114′, 115′described above, and at least one infrared antenna 106, 106′ above andconnected to the at least one temperature sensor. The method may alsoinclude generating infrared biometric data based upon infrared radiationemitted from the subdermal features of the user's finger.

Referring now to FIGS. 18 through 21, various embodiments ofmulti-biometric sensing pixel finger sensors 85, 85′ are firstdescribed. With particular reference to FIGS. 18 and 20, the electronicdevice is in the exemplary form of a cellular telephone 140 thatincludes a portable housing 141. The portable housing 141 carries amulti-biometric finger sensor 145, and a lighted keypad 142 that, inturn, includes a plurality of user operable input keys 143. The portablehousing 141 also carries a processor 144 that is connected to themulti-biometric sensor 145 and the optical source 147 for lighting thekeypad 142 via the optical guide 151. A display 148 is illustrativelycarried by the upper portion of the portable housing 141 and is alsoconnected to the processor 144.

The cellular phone 140 may also include a power source, such as arechargeable battery 152, carried by the portable housing 141 andconnected to the processor 144 and other electronic components withinthe housing as will be appreciated by those skilled in the art. A memory154 is also connected to the processor 144. The multi-biometric sensor145 includes an integrated circuit substrate 162, a first set ofbiometric sensing pixels 103 a on the integrated circuit substrate forsensing a first finger biometric characteristic to generate first fingerbiometric characteristic data having a first matching selectivity.

The sensor 145 also includes a second set of biometric sensing pixels103 b on the integrated circuit substrate 102 for sensing a secondfinger biometric characteristic different than the first fingerbiometric characteristic to generate second finger biometriccharacteristic data with a known spatial relationship to the firstfingerprint characteristic data. The second finger biometriccharacteristic data may have a second matching selectivity less than thefirst matching selectivity. Accordingly, a lower selectivitycharacteristic can be combined with a higher selectivity to provide moreaccurate results, for example, in a compact sensor package based onintegrated circuit technology.

The processor 144 is connected to first and second sets of sensingpixels 163 a, 163 b for generating the first and second biometriccharacteristic data. The first biometric characteristic data maycomprise fingerprint image data, for example. Other imaging dataestablishing known locations on the user's finger 160, such as basedupon minutiae patterns, could also be used, as well as other similardata establishing a known spatial relationship that may be correlated tothe second biometric characteristic data. Accordingly, for theseembodiments the processor 144 further illustratively includes a high/lowselectivity correlator 159 for cooperating with the first and secondsets of biometric sensing pixels 103 a, 103 b for spatially correlatingthe second finger biometric data relative to the fingerprint image data.To also provide a known temporal relationship between the data, theprocessor 144 may operate the first and second sets of biometric sensingpixels 103 a, 103 b substantially simultaneously.

A matcher 164 is connected to the correlator 169 for determining a matchbetween the multi-biometric data of the user's finger 160 and storedmulti-biometric biometric data for an enrolled user. This matchdetermination, in turn, may be used by a function enabler 165 of theprocessor 144 to enable at least one device function, such as permittingoperation of the transmit and receive functions of the cellulartelephone 140, for example. The correlator 169, the matcher 164, andenabler 165 may be implemented on a CPU of the processor operating understored program control, as will be appreciated by those skilled in theart without requiring further discussion herein.

Those of skill in the art will appreciate other device functions thatmay be controlled, such as access to data if the electronic device werea PDA, for example. Of course, many other electronic devices may benefitfrom the multi-biometric finger sensing, and these devices may includeother access limited functions. The multi-biometric characteristic datamay be accurately and efficiently obtained using the compact integratedcircuit-based sensor 145.

Another aspect of the infrared sensor 85 is that its processing may beself-contained on the integrated circuit substrate 162 itself, or, asshown in the illustrated embodiment, the integrated circuit may containsome of the processing circuitry 167. For example, pixel readingamplifiers and/or other image processing active devices may be providedon the substrate 162 using conventional CMOS technology, for example. Inyet other embodiments, all or a majority of the signal processingcircuitry may be located off-chip. The integrated circuit substrate 162may preferably a silicon substrate as will be appreciated by thoseskilled in the art.

The illustrated embodiment of the multi-biometric sensor 145 is a staticplacement sensor. In other words, the size of the array of pixels 163 a,163 b is relatively large compared to a sliding placement sensor asdiscussed below. Also, for the static placement sensor 145, theprocessor 144 generates the multi-biometric characteristic data basedupon static placement of the user's finger adjacent the integratedcircuit substrate 162.

Referring now more particularly to FIGS. 19 and 21, another class ofembodiments of multi-biometric finger sensors 145′ is now described. Inthese embodiments, the illustrated multi-biometric sensor 145′ is in theform of a sliding placement sensor that has a smaller sensing area overwhich the user slides his finger 160′ as will be appreciated by thoseskilled in the art. In these embodiments, the processor 144′ may collectframes of infrared biometric data from the sensing pixels 103 a′, 103b′.

U.S. Pat. No. 5,351,303 to Willmore schematically discloses a contactsensor for reading the infrared profile of the finger, but no successfulimplementation of the method described is known to date. Such aninfrared sensor may suffer from sensitivity to both conducted thermalenergy and radiated thermal energy. In the finger contact application,the conducted thermal energy is generally dominant, and in it thepattern of the finger surface friction ridges dominates. The patterns ofthe subdermal sources, such as the arterial blood supply are overwhelmedby the strong ridge pattern signal. While reading the friction ridgepattern can be useful, that is not typically required for the infraredsensors in the multi-biometric sensor embodiments. In this case, thefriction ridge pattern is noise, and the pattern of the subdermalfeatures sources is the unique data the sensor is attempting to capture.

The infrared sensor arrays of the prior art may also suffer from theomni-directional sensitivity pattern of the pixels. Crosstalk betweenpixels may become a debilitating problem if the thermal structures to beimaged are farther away from the array than 3 or 4 times the pixelpitch. This is indeed the case when imaging the subdermal structures ofthe finger. To be successful, the pixels should have some form offocusing that minimizes crosstalk.

The infrared sensors 85, 85′ as disclosed herein may use a differentialthermal sensing that rejects heat conducted through the surface of thedevice (that contains primarily the friction ridge pattern) and detectsradiant infrared heat (which contains patterns primarily representativeof the subdermal arterial blood distribution). The antenna andtemperature sensor structure provides the focusing to reduce or minimizecrosstalk between the pixels and develop clean image of the subdermalthermal pattern. The infrared sensors 85, 85′ can be fabricated inexisting standard CMOS silicon foundry processes as will be appreciatedby those skilled in the art.

Those other elements of the embodiment of the cellular telephone 140′shown in FIGS. 18 and 21 are similar to those of the embodimentdescribed above with respect to FIGS. 18 and 20, and are indicated withprime notation. Accordingly, these elements require no furtherdiscussion herein,

Referring now additionally to FIG. 22, an embodiment of a highselectivity biometric characteristic sensing pixel 163 a in the form ofan electric field sensing pixel is now described. The electric fieldsensing pixel 163 a may also be considered or referred to as an RFsensing pixel in view of its operating frequency as described below.

In particular, the electric field sensor pixel 163 a includes one ormore active semiconductor devices formed on the substrate 162, such asthe schematically illustrated amplifier 180. A first metal layer 181interconnects the active semiconductor devices. A second or ground planeelectrode layer 182 is above the first metal layer 181 and separatedtherefrom by an insulating layer 184. A third metal layer 185 ispositioned over another dielectric layer 186. In the illustratedembodiment, the a first external electrode 190 is connected to anexcitation drive amplifier 191 which, in turn, drives the finger 160with a signal that may be typically in the range of about 1 KHz to 1MHz. Accordingly, the drive or excitation electronics are thusrelatively uncomplicated and the overall cost of the electric fieldsensing pixel 163 a may be relatively low, while the reliability isgreat.

An illustratively circularly shaped electric field sensing electrode 192is on the insulating layer 186. The sensing electrode 192 may beconnected to sensing integrated electronics, such as the illustratedamplifier 180 formed adjacent the substrate 162 as schematicallyillustrated, and as would be readily appreciated by those skilled in theart.

An annularly shaped shield electrode 195 surrounds the sensing electrode192 in spaced relation therefrom. As would be readily appreciated bythose skilled in the art, the sensing electrode 195 and its surroundingshield electrode 195 may have other shapes, such as hexagonal, forexample, to facilitate a close packed arrangement or array of sensingpixels. The shield electrode 195 is an active shield which is driven bya portion of the output of the amplifier 180 to help focus the electricfield energy and, moreover, to thereby reduce the need to drive adjacentelectric field sensing electrodes.

The electric field sensing pixel 163 a also illustratively includes anupper passivation layer 197, and an optional ESD electrode 196. Theelectric field sensor pixel 163 a includes only three metal orelectrically conductive layers 181, 182 and 185/195. The sensing pixels163 a can be made without requiring additional metal layers that wouldotherwise increase the manufacturing cost, and, perhaps, reduce yields.Accordingly, the overall multi-biometric sensor 145 may less expensiveand may be more rugged and reliable than a sensor including four or moremetal layers as would be appreciated by those skilled in the art. Aswill be appreciated by those skilled in the art, the construction of theelectric field sensing pixels 163 a is also fully compatible with theoptical dispersion and/or infrared sensing pixels described herein.

The electric field sensing pixel 163 a and various processing featuresand further advantages are disclosed, for example, in U.S. Pat. No.5,953,441 to Setlak and assigned to the assignee of the presentinvention. The entire contents of this Setlak patent are incorporatedherein by reference. The patent also discloses use of the electric fieldsensing pixel 163 a to determine a complex impedance of the user'sfinger to thereby aid in reducing the likelihood of spoofing the sensorwith other than a live finger. In the present multi-biometric sensor145, the electrical field sensing pixel 163 a could also be used incomplex impedance measuring as another biometric characteristic of theuser to aid in efficient matching.

Each of the second set of biometric sensing pixels of themulti-biometric sensor 145 may comprise an optical dispersion sensingpixel 163 b for sensing dispersed light from the user's finger, incombination with the electric field sensing pixels as shown anembodiment of FIG. 23. In this embodiment, the electric field drive ring190 extends around the periphery, and the two pixel types areintermingled in the sensing area. The light source is provided by thesurface emitting LED 200 carried by the integrated circuit substrate162.

Another possible layout of the optical dispersion sensing pixels 163 b′and electric field sensing pixels 163 a′ is shown in FIG. 24. In thisembodiment of a multi-biometric sensor 145′, the optical dispersionpixels are arranged in first and second groups flanking the array ofelectric field sensing pixels 163 a′. The finger drive electrode 162′ isalso shown as two segments on the outside of the respective first andsecond groups of optical dispersion sensing pixels 163 b′. In thisembodiment, the light source 200′ is provide from off the integratedcircuit substrate 162′.

Turning now additionally to FIG. 25, advantageous processing of themulti-biometric data from a multi-biometric finger sensor 210 isdescribed. The illustrated multi-biometric sensor 210 is of the slidetype including electric field sensing pixels and optical dispersionpixels as described above. The optical source 212 is located on theintegrated circuit substrate in the illustrated embodiment. A staticplacement multi-biometric sensor may produce similar data as will beappreciated by those skilled in the art.

In particular, a first sequence of relative intensity data isillustrated by the image blocks 213 a-213 a-213 d. The light intensityis sequentially sensed at two spaced points in the X-direction, that is,the direction of advancement of the user's finger 215, the intensity atthese two spaced positions is plotted in the upper and lower curves ofthe graph 216. As expected, the curve from the location closer to theoptical source 212 is greater than from the other spaced location. Asalso shown, a difference between these two curves is determined andplotted in the graph 217. As can be seen the difference in local lightdispersion seen in lower graph 217 varies with position along thefinger.

Referring now briefly to the curves of FIGS. 26, 27 and 28 for differentindividuals A, B and C, it can be seen that the optical dispersion dataso compiled is indeed unique to the different individuals over repeatedmeasurements. Accordingly, the optical dispersion data so processed mayserve as a valuable biometric matching characteristic especially incombination with the higher selectivity provide by the fingerprintfriction ridge image sensing provided by the electric field sensingpixels.

Returning now again to FIG. 25, and the right hand side thereof, aseries of optical images enhanced to show ridges, valleys, pores, etc.is shown. As noted in Block 220 these enhanced images can be matched andused to establish exact locations of the frames along the finger 215. Asnoted at processing Block 221 the enhanced images can also be used byclassical fingerprint matching. Moreover, subdermal structures, such aspores are especially clear in optical dispersion images.

Referring now additionally to FIG. 29, another multi-biometric sensor225 is now described. In this embodiment, infrared sensing pixels 227 onthe integrated circuit substrate 232 provide the second set of biometricsensing pixels having the lower selectivity, while electric fieldsensing pixels 228 provide the sensing pixels having the higher matchingselectivity. A drive electrode 233 is also illustratively positionedaround the periphery of the sensor 225. Of course, exemplary embodimentsof infrared sensing pixels are extensively described above and need nofurther description here. If the operating frequencies of the differentsensing pixels 227, 228 is sufficiently different, e.g. on the order of10⁶ Hz apart, it is likely that both types of sensing pixels can beoperated simultaneously. Those of skill in the art will appreciate inthat other embodiments, the selectivity of the electric field sensingpixels 228 could be less than the infrared sensing pixels 227, such asby altering the relative numbers of each, for example.

With additional reference to FIG. 30, another multi-biometric sensingand matching system 235 is now explained. In this embodiment, a numberof the above-described biometric finger characteristic sensing andprocessing aspects are combined. The system 235 illustratively includesa multi-biometric sensor 236 coupled to a multi-biometric matcher 237.The multi-biometric sensor 236 includes an integrated circuit substrate240 upon which electric field sensing pixels 241, optical dispersionsensing pixels 242, and infrared sensing pixels 243 are provided.

A processor executing a respective software module performs complex skinimpedance measuring using the electric field sensing pixels 241 at Block245. The electric field sensing pixels 241 are also operated to generatea friction ridge pattern by Block 246. Similarly, Block 247 produces anoptical dispersion skin pattern from the optical dispersion sensingpixels 242. In addition, the infrared sensing pixels are used togenerate subdermal thermal or infrared patterns by Block 250. The dataproduced by Blocks 245, 246, 247 and 250 is illustratively fed to Block251 for signal processing and data conversion.

The outputs of the signal processing and data conversion Block 251 arecoupled to several modules or Blocks in the multi-biometric matcher 237.In particular, the finger impedance matcher of Block 255 receives anoutput, as do the finger pattern matcher of Block 256, the fingeroptical dispersion pattern matcher of Block 260, and the thermal patternmatcher of Block 257. As explained above, it may be desirable tospatially correlate the thermal or infrared pattern data and opticaldispersion data to a finger location and this is done by couplingoutputs of the fingerprint pattern matcher of Block 256 to Blocks 257and 260.

Lastly as shown in the illustrated system 235 Block 261 may be used toperform a statistical match decision. This may be done by a simplevoting algorithm or by more sophisticated weighting algorithms as willbe appreciated by those skilled in the art.

The types of multi-biometric sensors disclosed herein, containing amixture of different sensor types has several advantages over bothtraditional single biometric sensors, and over non-integrated sets ofmulti-biometric measurements. Multiple biometrics methods can besatisfied simultaneously and in the same small physical space. Thetemporal and spatial simultaneity requirement makes spoofing moredifficult. The sensors are easy and convenient use, as the user canprovide a single presentation of a single body part, such as the finger,while generating multiple biometric measurements for use in highaccuracy identification and identity verification, greatly simplifyingand speeding up multi-biometric measurements. The sensors provide asingle acquisition/signal-processing device that integrates themeasurement of several different biometric characteristics, eliminatingthe need for multiple independent reading devices and signal processingsystems, and eliminating the excessive equipment cost of prior artmulti-biometric systems.

An advantage of the multi-biometric sensor embodiments disclosed hereinis that they can use biometric measurements that, by themselves, haveonly a limited degree of selectivity between people. Theselow-selectivity biometrics have rarely been exploited in the pastbecause by themselves they are not very useful. A combination of severalof these biometrics, however, if they are statistically orthogonal andacquired simultaneously, can have a joint selectivity that approachesthe mathematical product of the individual selectivities. Less selectivebiometrics can be combined with stronger biometrics, such as fingerprintverification, to yield a system with very strong selectivity that ismuch more difficult to spoof than the single high-selectivity biometricalone, such as the fingerprint alone.

Some of the secondary biometrics, such as finger thermal profile,generate very diffuse image characteristics. Since there are no definiteedges in the images, it is difficult find the proper alignment formatching. When an image of the same area is taken simultaneously usingboth a strongly edged characteristics, e.g. the fingerprint, and adiffuse characteristic, e.g. the finger thermal profile, the exactalignment of the match data with the template can be established usingthe edged characteristic. This alignment can then be applied to thediffuse characteristic, permitting a higher confidence match assessmentof that characteristic. The result is a small, inexpensive, easy to usemulti-biometric sensor that has performance exceeding that of thetraditional biometric systems, both in terms of match accuracy and spoofreduction.

The multi-biometric sensors described herein are envisioned asfabricated on a silicon integrated circuit substrate, with the varioussensors and signal processing integrated into the silicon. The userplaces his finger on the device, and the system reads several differentproperties or biometric characteristics of the finger skin adjacent tothe sensor simultaneously. Examples of the kind of biometricmeasurements and sensors that could be used include any of the variouskinds of sensing mechanisms known to measure the physical friction ridgestructure of the skin. Such sensors include optical systems, RF imagingsystems, contact temperature and thermal flux systems, electricalcapacitance systems, pressure measuring systems, vibration dampingsystems, ultrasonic systems, etc. Also possible are electronicmechanisms for detecting the bulk electrical and electromagneticproperties of the skin, such as electrical impedance sensors. Inaddition, sensing mechanisms for detecting the optical transmission ofdispersion properties of the skin such as photo-detectors,photo-emitters, filters, gratings, coatings, etc. may be used in yetother embodiments.

Devices that measure the subdermal thermal profile of the finger such asInfrared cameras, and infrared sensor arrays could also be used. Sensorsthat detect properties of the blood, cardiac pulse, or other innerstructures of the skin, such as pulse-oximetry detectors, deep readingoptical or infrared emitters and detectors, pulse pressure sensors etc.may be used in other embodiments. In addition, sensors can be used thatmeasure the bulk mechanical stiffness or low frequency mechanicaldamping properties of the skin, such as force gages or stain gages,pressure sensing elements, vibrating elements, accelerometers, etc.Other sensors that measure properties of the layered structures of theskin, such as ultrasonic transducers, may be used. Devices that measureskin surface chemistry, such as semiconductor electrolyte ion detectors,etc. may also be used in various other embodiments of themulti-biometric sensors described herein as will be appreciated by thoseskilled in the art.

Other related features and aspects of the sensors described herein maybe found in copending patent applications entitled FINGER SENSOR USINGOPTICAL DISPERSION SENSING AND ASSOCIATED METHODS, Ser. No. 10/935,482;MULTI-BIOMETRIC FINGER SENSOR INCLUDING OPTICAL DISPERSION SENSINGPIXELS AND ASSOCIATED METHODS, Ser. No. 10/935,705; MULTI-BIOMETRICFINGER SENSOR USING DIFFERENT BIOMETRICS HAVING DIFFERENT SELECTIVITIESAND ASSOCIATED METHODS, Ser. No. 10/935,704; INFRARED BIOMETRIC FINGERSENSOR INCLUDING INFRARED ANTENNAS AND ASSOCIATED METHODS, Ser. No.10/935,484; INFRARED BIOMETRIC FINGER SENSOR AND ASSOCIATED METHODS,Ser. No. 10/935,468; ELECTRONIC DEVICE INCLUDING OPTICAL DISPERSIONFINGER SENSOR AND ASSOCIATED METHODS, Ser. No. 10/935,472; andMULTI-BIOMETRIC FINGER SENSOR INCLUDING INFRARED SENSING PIXELS ANDASSOCIATED METHODS, Ser. No. 10/935,483, assigned to the assignee of thepresent invention and the entire subject matter of which is incorporatedherein by reference. Many modifications and other embodiments of theinvention will come to the mind of one skilled in the art having thebenefit of the teachings presented in the foregoing descriptions and theassociated drawings. Therefore, it is understood that the invention isnot to be limited to the specific embodiments disclosed, and thatmodifications and embodiments are intended to be included within thescope of the appended claims.

1. A multi-biometric finger sensor apparatus comprising: an integratedcircuit substrate for receiving a user's finger adjacent thereto; aplurality of electric field fingerprint sensing pixels on saidintegrated circuit substrate for sensing an image of the user's finger,each of said plurality of electric field fingerprint sensing pixelscomprising an electric field sensing electrode, a guard shieldsurrounding said electric field sensing electrode, and an amplifierconnected between said electric field sensing electrode and said guardshield, at least one other finger biometric characteristic sensor onsaid integrated circuit substrate for sensing a finger biometriccharacteristic different than the image of the user's finger; a fingerdrive electrode adjacent said plurality of electric field sensingpixels; and a processor connected to said plurality of electric fieldfingerprint sensing pixels and said at least one other finger biometriccharacteristic sensor.
 2. A multi-biometric finger sensor apparatusaccording to claim 1 wherein said at least one other finger biometriccharacteristic sensor comprises a plurality of infrared sensing pixels.3. A multi-biometric finger sensor apparatus according to claim 2wherein each of said infrared sensing pixels is for sensing naturallyemitted infrared radiation from the user's finger.
 4. A multi-biometricfinger sensor apparatus according to claim 1 said at least one otherfinger biometric characteristic sensor comprises at least one opticaldispersion sensing pixel for sensing dispersed light from the user'sfinger.
 5. A multi-biometric finger sensor apparatus according to claim4 further comprising an optical source for directing light into a user'sfinger when positioned adjacent said integrated circuit substrate, thelight propagating into and being dispersed by the user's finger so thatat least a portion of the dispersed light exits the user's finger in adirection toward said integrated circuit substrate.
 6. A multi-biometricfinger sensor apparatus according to claim 1 further comprising amatcher connected to said electric field finger sensing pixels and saidat least one other biometric sensor.
 7. A multi-biometric finger sensorapparatus according to claim 1 wherein said electric field fingersensing pixels and said at least one other finger biometric sensoroperate based upon static placement of the user's finger adjacent saidintegrated circuit substrate.
 8. A multi-biometric finger sensorapparatus according to claim 1 wherein said electric field fingersensing pixels and said at least one other finger biometric sensoroperate based upon sliding placement of the user's finger adjacent saidintegrated circuit substrate.
 9. A multi-biometric finger sensorapparatus according to claim 1 further comprising an uppermostdielectric passivation layer over said plurality of electric fieldsensing pixels and said at least one other biometric sensor and uponwhich the user's finger is positioned.
 10. A multi-biometric fingersensor apparatus according to claim 1 wherein said integrated circuitsubstrate comprises single crystal silicon.
 11. A multi-biometric fingersensor comprising: an integrated circuit substrate for receiving auser's finger adjacent thereto; a plurality of electric fieldfingerprint sensing pixels on said integrated circuit substrate forsensing an image of the user's finger, each of said plurality ofelectric field fingerprint sensing pixels comprising an electric fieldsensing electrode, a guard shield surrounding said electric fieldsensing electrode, and an amplifier connected between said electricfield sensing electrode and said guard shield; and a plurality of fingerbiometric characteristic sensing pixels on said integrated circuitsubstrate for sensing a finger biometric characteristic different thanthe image of the user's finger.
 12. A multi-biometric finger sensoraccording to claim 11 wherein each of said plurality of finger biometriccharacteristic sensing pixels comprises an infrared sensing pixel.
 13. Amulti-biometric finger sensor according to claim 12 wherein each of saidinfrared sensing pixels is for sensing naturally emitted infraredradiation from the user's finger.
 14. A multi-biometric finger sensoraccording to claim 11 each of said plurality of finger biometriccharacteristic sensing pixels comprises a plurality of opticaldispersion sensing pixels for sensing dispersed light from the user'sfinger.
 15. A multi-biometric finger sensor according to claim 14further comprising an optical source for directing light into a user'sfinger when positioned adjacent said integrated circuit substrate, thelight propagating into and being dispersed by the user's finger so thatat least a portion of the dispersed light exits the user's finger in adirection toward said integrated circuit substrate.
 16. Amulti-biometric finger sensor according to claim 11 wherein saidelectric field finger sensing pixels and said plurality of fingerbiometric characteristic sensing pixels operate based upon staticplacement of the user's finger adjacent said integrated circuitsubstrate.
 17. A multi-biometric finger sensor according to claim 11wherein said electric field finger sensing pixels and said plurality offinger biometric characteristic sensing pixels operate based uponsliding placement of the user's finger adjacent said integrated circuitsubstrate.
 18. A multi-biometric finger sensor according to claim 11further comprising an uppermost dielectric passivation layer over saidplurality of electric field sensing pixels and said plurality of fingerbiometric characteristic sensing and upon which the user's finger ispositioned.
 19. A multi-biometric finger sensor according to claim 11wherein said integrated circuit substrate comprises single crystalsilicon.
 20. A method for multi-biometric finger sensing comprising:receiving a user's finger adjacent an integrated circuit substrate;sensing an image of the user's finger by using a plurality of electricfield fingerprint sensing pixels on the integrated circuit substrate,each electric field fingerprint sensing pixel comprising an electricfield sensing electrode, a guard shield surrounding the electric fieldsensing electrode, and an amplifier connected between the electric fieldsensing electrode and the guard shield; and sensing a finger biometriccharacteristic different than the image of the user's finger by using atleast one other finger biometric characteristic sensor on the integratedcircuit substrate.
 21. A method according to claim 20 further comprisinga finger drive electrode adjacent the plurality of electric fieldsensing pixels.
 22. A method according to claim 20 wherein the at leastone other finger biometric characteristic sensor comprises a pluralityof infrared sensing pixels.
 23. A method according to claim 22 whereineach of the infrared sensing pixels is for sensing naturally emittedinfrared radiation from the user's finger.
 24. A method according toclaim 20 wherein the at least one other finger biometric characteristicsensor comprises a plurality of optical dispersion sensing pixels forsensing dispersed light from the user's finger.
 25. A method accordingto claim 24 further comprising an optical source for directing lightinto a user's finger when positioned adjacent the integrated circuitsubstrate, the light propagating into and being dispersed by the user'sfinger so that at least a portion of the dispersed light exits theuser's finger in a direction toward the integrated circuit substrate.26. A method according to claim 20 further comprising a matcherconnected to the electric field finger sensing pixels and the at leastone other biometric sensor.
 27. A method according to claim 20 whereinthe electric field finger sensing pixels and the at least one otherfinger biometric sensor operate based upon static placement of theuser's finger adjacent the integrated circuit substrate.
 28. A methodaccording to claim 20 wherein the electric field finger sensing pixelsand the at least one other finger biometric sensor operate based uponsliding placement of the user's finger adjacent the integrated circuitsubstrate.
 29. A method according to claim 20 further comprising anuppermost dielectric passivation layer over the plurality of electricfield sensing pixels and the at least one other biometric sensor andupon which the user's finger is positioned.